Rams for pile-drivers and the like



May 21, 1957 Filed May 4, 1953 G. OYER 2,792,816

RAMS FOR FILE-DRIVERS AND THE LIKE 2 Sheets-Sheet 1 INVENTOR.

May 21, 1957 G. OYER 2,792,816

RAMS FOR FILE-DRIVERS AND THE LIKE Filed May 4, 1953 2 Sheets-Sheet 2 INVENTOR.

United States Patent 'i cc.

This invention relates to power rams of the internal combustion type, for driving piles, sheet-piling and the like. Rams of this type cannot operate, or at least do not operate 'well,when they have to drive stakes or sheetpiling'for example into soft ground. Dificulties are experienced with the initial insertion, for when the beat- 1 ing startsthe embedding takes place to a greater or less extent merely as a result of the compression. This sinking absorbs a part of the work corresponding to the fall of the weight, and this has the result that the air sucked into the cylinder does not reach a temperature corresponding to the temperature of spontaneous ignition of the fuel utilised. It therefore becomes necessary to raise the impact weight mechanically by means of its carriage a. certain number of times, thus constituting a vertible monkey-beating phase by disengagement of a catch, such as was practiced with the earliest pile-drivers.

This striking from the detent has to be continued until the resistance of the soil entails sufficient work in compressing the air contained in the cylinder to raise the air to the proper temperature.

The object of the present invention is to reduce to the utmost the number of mechanical lifts of the detent carriage that must be effected before automatic operation is attained.

A further object is to promote combustion by creating a violent movement of the air or of the mixture of air and fuel.

According to the present invention, only a portion of the volume of air subjected to the action of the piston is compressed to the pressure corresponding to the point of spontaneous ignition of the mixture.

The invention is carried out by causing the formation, in the course of the fall, of two distinct compression spaces or chambers, such that the volumetric ratio increases more rapidly in one than in the other, so that the temperature of spontaneous ignition is reached only in the smaller fraction of the initial volume, means being provided for propagating the ignition to the compression space of lower pressure.

On the otherhand the means provided for allowing the combustion to propagate itself into the second part of the compression space gives rise to a violent movement of the air and/or of the mixture, the effects of this movement being artificially augmented according to a further feature of the invention.

Examples of the manner in which the invention is carried out will now be given, without the general scope of the invention being restricted to or by the specific details of the examples selected for purposes of illustration.

In the accompanying drawings, Figures 1, 2 and 3 relate to the application of the invention to an automotive ram for pulverisation by impact. They represent diagrammatically in axial section three different positions of the ram.

2,792,816 Patented May 21, 1957 Figure 4 shows a section on the line IV--IV in Fig ure 2.

Figure 5 relates to the application of the invention to the case of the atomisation and injection of the fuel in the explosion chamber when the pressure therein has reached its maximum; and

Figures 6 and 7 relate to the application of the invention to the injection and atomisation of the fuel in the compression chamber during the up stroke of .the piston.

In Figures 1, 2, 3 and 4, 10 denotes the cylinder, containing the ram 11, which serves as a piston. At the base of this cylinder is an anvil 12, so constituted as to form an internal jacket of substantial thickness.

The piston 11 has a portion 13 of reduced diameter, corresponding to the internal diameter of the jacket of the anvil 12.. Finally the piston may terminate in a nipple 14,adapted to lodge in a cavity 15 in the anvil, and to effect by impact the atomisation of the fuel injected in liquid form into the cavity15.

Figure 1 represents the ram in its raised position.

Figure 2represents the ram at themoment when the part 13, of reduced diameter, is about to engage in the jacket of the anvil. It will be seen that from this moment onwards there are two separate spaces or chambers 16 and 17.

The internal diameter of the jacket and the height of the reduced part 13 are so selected that the final volumetric ratio of compression will be higher in the space 16 than in the space 17.

Finally, in the part 13, ducts such as 18 have been provided, establishing communication between the spaces 16 and 17. These ducts 18 may have a part parallel to the axis of the cylinder, but according to the invention they will open into the space 17 by passages 19 which are not in a radial direction but in a very oblique direction, as shown in Figure 4. The cylinder 10 is provided with at least one port 10A spaced from the anvil 12 and such port serves as an exhaust port for the gases as well as an air delivery port.

This apparatus operates in the following manner: The ram being at the top of its stroke, as in Figure 1, fuel in liquid form is injected by an injector 20 into the cavity 15 of the anvil. From the moment when the part 13 of the piston which is of reduced diameter enters the jacket, two distinct spaces 16 and 17 are created, the compression in the space 16 increasing more rapidly than in the space 17 and the port 10A is sealed by the piston. Under these conditions the temperature will rise much more rapidly in the space 16 than in the space 17, and will more readily reach the temperature corresponding to spontaneous ignition of the fuel mixture. Between the position represented in Figure 2 and the ultimate position represented in Figure 3, a violent impulsion of air will be established through the passages 18 and 19, producing a violent gyratory movement in the space 17, owing to the arrangement of the passages 19. Upon the ram striking violently upon the anvil, as represented in Figure 3, the fuel will be atomised and will ignite spontaneously, in view of the temperature reached.

From this moment onwards, a very rich mixture in the course of combustion will be violently blown from the space 16 towards the space 17, and will then proceed to complete combustion on contact with the air contained in the space 17.

The gyratory motion in the space 17 will be highly favourable to a very rapid and very complete combustion. From this moment onwards, the cycle of operations will be initiated automatically.

The drawings show, at 21, grooves which restrict leakages between the two spaces 16 and 17.

In Figure 5, the'inetho'd according to the invention has been illustrated, as applied to a ram for atomisation by injectors 22. In this Figure 5 the piston 11 has been respresented at the end of its fall at the moment when the injectors 22 are atomising the fuel, which ignites on contact with the compressed air in the space 16, which then'const'itutes the explosion chamber.

In Figures 6 and 7 "the introduction of the vfuel is effected by injectors .23, which atomise the fuel in the compression chamber, that is to say, during the ascending stroke of the piston, as shown in Figure 6.

Figure 7 represents the piston at the lower end of its stroke, at the moment when the explosion is produced in the space 16, in which the temperature of the compressed air is sufficient to occasion the'spontaneous ignition of the fuel mixture.

What I claim is: r

1. A power ram including an elongated cylinder, an anvil at one end of said cylinder, an air delivery and gas exhaust port in said cylinderspaced from said anvil, said anvil being provided with a concentric cylindrical cavity of substantial length and of lesser diameter than the elongatedcylinder, a piston reciprocably mounted within the cylinder for movement toward and away from the anvil, said piston having a concentric cylindrical boss of a size to fit snugly within the cylindrical cavity and of a length greater than the depth of the cavity, so that when the boss begins" to enter the cavity, two compression chambers are formed with the dimensions of such chambers being such that the ratio of compression increases more rapidly in the cavity than in the other chamber, the piston sealing the port when the boss is within the cavity, means to introduce fuel into the cavity, and means defining a permanent path of communication between the two chambers when the boss enters the cavity.

2. A power ram as defined in claim 1 wherein the means defining the permanent path of communication includes ducts extending parallel to the axis of the cylindrical boss for the greater portion of their length and opening into the chamber of larger diameter in directions constituting a substantial angle with the radii of the boss.

References Cited in the file of this patent UNITED STATES PATENTS Jordan Sept. 4, 1945 

